RAIL TIE PAD

Abstract

A rail tie pad for use with a cast rail tie. The rail tie pad may be flexible, polymeric body having first and second opposite sides and, when viewed in cross-section, includes an upper surface and a lower surface defining a first vertical thickness and including a plurality of undulations with alternating concave portions and convex portions. The rail tie pad further includes a pair of side anchor portions respectively disposed at the first and second opposite sides of the pad, each including at least one anchor projection for embedment within the side portions of a cast rail tie. In this manner, the anchor portions of the rail tie pad are embedded within, and fixably secure, the sides of the rail tie pad to the cast rail tie to mitigate or prevent separation of the rail tie pad from the rail tie during transport and/or positioning of the rail tie during installation.

Description

BACKGROUND OF THE DISCLOSURE

1. Field of the Disclosure

The present disclosure relates to rail tie pads of the type used to support rail ties in a railway system and, in particular, relates to a rail tie pad including a flexible, polymeric body which is joined to a cast rail tie for supporting the rail tie in a rail bed and for attenuating vibrations from passing engines and railcars.

2. Description of the Related Art

In a railway system, rails are supported by a large number of rail ties or sleepers, which are supported in a rail bed that is formed of a ballast such as aggregate material. The ballast may be supported on a bed of sub-ballast, which in turn may be supported on a formation, subgrade, and/or foundation. Passing train engines and railcars cause vibrations throughout the rails and the rail ties which are transferred through such components to the ballast and other support grades. To attenuate the vibrations and provide an extended service life of the rails and rail ties, rail tie pads are provided to support the rail ties within the ballast, and are typically made of a flexible, polymeric material.

The rail tie pads may be positioned or seated between the rail ties and the ballast without any physical connection between the rail ties and the rail tie pads, or the rail tie pads may be joined to the rail ties via an adhesive, for example. In other configurations, the rail ties are formed of a cast material, such as concrete or a composite material, and the rail tie pads are integrally joined to the cast rail ties by the embedment of anchoring features of the rail tie pads within the cast material of the rail ties at the time of casting the rail ties.

When using rail pads that are joined to the rail ties, either via adhesive or partial embedment of the rail tie pads within the cast rail ties, problems may occur based on partial or complete separation of the rail tie pads from the rail ties prior to installation of the rail ties within the ballast during assembly of the railway system and/or during repair or replacement of rail ties within an existing railway system. For example, when rail ties are moved using a forklift, the ends of the fork tines of the forklift may contact the rail tie pads and strip them away from their associated rail ties and/or may lodge between the rail tie pads and the rail ties and separate or dislodge the rail tie pads from the rail ties.

What is needed is an improvement over the foregoing.

SUMMARY

The present disclosure provides a rail tie pad for use with a cast rail tie. The rail tie pad may be flexible, polymeric body having first and second opposite sides and, when viewed in cross-section, includes an upper surface and a lower surface defining a first vertical thickness and including a plurality of undulations with alternating concave portions and convex portions. The rail tie pad further includes a pair of side anchor portions respectively disposed at the first and second opposite sides of the pad, each including at least one anchor projection for embedment within the side portions of a cast rail tie. In this manner, the anchor portions of the rail tie pad are embedded within, and fixably secure, the sides of the rail tie pad to the cast rail tie to mitigate or prevent separation of the rail tie pad from the rail tie during transport and/or positioning of the rail tie during installation.

In one form thereof, the present disclosure provides a rail tie pad for use with a cast rail tie, including a flexible, polymeric body having first and second opposite sides and including, when viewed in cross-section: an upper surface and a lower surface defining a first vertical thickness therebetween, and each including a plurality of undulations with alternating concave portions and convex portions; and a pair of side anchor portions respectively disposed at the first and second opposite sides of the pad, the side anchor portions each having a second vertical thickness greater than the first vertical thickness, each side anchor portion extending upwardly from the upper surface and including at least one anchor projection for embedment within a cast rail tie.

The concave portions of the undulations of the upper surface may be vertically aligned with the convex portions of the undulations of the lower surface, and the convex portions of the undulations of the upper surface may be vertically aligned with the concave portions of the undulations of the lower surface.

The side anchor portions may each extend substantially entirely along the first and second opposite sides of the pad. The rail tie pad may further include at least one central anchor portion disposed between the pair of side anchor portions, each central anchor portion having a third vertical thickness greater than the first vertical thickness and extending upwardly from the upper surface, each central anchor portion further including at least one anchor projection for embedment within a cast rail tie.

The side anchor portions may each have a substantially triangular profile when viewed in cross-section, and also may include vertical outermost walls which, when the rail tie pad is cast within a cast rail tie, are disposed substantially vertically flush with side walls of the cast rail tie. When viewed in cross-section, the vertical outermost walls of the side anchor portions may each be joined to the lower surface of the rail tie pad via a rounded corner. The anchor projections of the side anchor portions may each extend at an angle with respect to the top surface of the rail tie pad.

The polymeric body may be made of an elastomer having a hardness between 50 Shore A and 80 Shore A.

In another form thereof, the present disclosure provides a cast rail tie, including a cast tie body including a top side, a bottom side, and a plurality of side walls; and a rail tie pad joined to the bottom side of the cast body, the rail tie pad including a flexible, polymeric body having first and second opposite sides and, when viewed in cross-section, an upper surface and a lower surface defining a first vertical thickness therebetween, the rail tie pad further including a pair of side anchor portions respectively disposed at the first and second opposite sides of the pad, each side anchor portion including at least one anchor projection adapted for embedment within a cast rail tie.

The side anchor portions may extend substantially entirely along the first and second opposite sides of the rail tie pad, and/or may each extend upwardly from the upper surface and have a second vertical thickness greater than the first vertical thickness. The side anchor portions of the rail tie pad may each include vertical outermost walls which are disposed substantially vertically flush with respective side walls of the cast tie body. The side anchor portions of the rail tie pad, when viewed in cross section, may extend vertically upwardly beyond the bottom side of the cast tie body.

When viewed in cross-section, the vertical outermost walls of the side anchor portions of the rail tie pad may each be joined to the lower surface of the rail tie pad via a rounded corner. The anchor projections of the side anchor portions may extend at an angle with respect to the top surface of the rail tie pad.

The upper surface and the lower surface of the rail tie pad may each include a plurality of undulations with alternating concave portions and convex portions. The concave portions of the undulations of the upper surface may be vertically aligned with the convex portions of the undulations of the lower surface of the rail tie pad, and the convex portions of the undulations of the upper surface may be vertically aligned with the concave portions of the undulations of the lower surface of the rail tie pad.

The rail tie pad may further include at least one central anchor portion disposed between the pair of side anchor portions, each central anchor portion having a third vertical thickness greater than the first vertical thickness and extending upwardly from the upper surface, each central anchor portion further including at least one anchor projection embedded within the cast tie body.

The material of the cast tie body may entirely fill each of the concave portions of the undulations of the upper surface of the rail tie pad.

DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side view of a portion of an exemplary railway system;

FIG. 2 is a perspective view of a rail tie pad in accordance with the present disclosure;

FIG. 3 is a sectional view taken along line 3-3, the rail tie pad of FIG. 2;

FIG. 4 is a partial sectional view of a portion of the rail tie pad of FIG. 3, showing same embedded within a cast rail tie;

FIG. 5 is a sectional view showing a cast rail tie and rail tie pad of FIGS. 2-4 positioned in a rail bed;

FIG. 6 is a partial sectional view of a portion of the rail tie pad of FIGS. 2-4 according to an alternate embodiment;

FIG. 7 is a sectional view of a rail tie pad according to an alternate embodiment;

FIG. 8 is a partial sectional view of a portion of the rail tie pad of FIG. 7, showing same embedded within a cast rail tie;

FIG. 9 is a sectional view showing a cast rail tie and rail tie pad of FIGS. 6 and 7 positioned in a rail bed;

FIG. 10 is a sectional view of a rail tie pad according to an alternate embodiment;

FIG. 11 is a partial sectional view of a portion of the rail tie pad of FIG. 10, showing same embedded within a cast rail tie;

FIG. 12 is a sectional view showing a cast rail tie and rail tie pad of FIGS. 10 and 11 positioned in a rail bed; and

FIG. 13 is a sectional view showing a rail tie pad according to an alternate embodiment embedded within a cast rail tie.

DETAILED DESCRIPTION

Referring to FIG. 1, a portion of an exemplary railway system 10 is shown, including rails 12 supported by a suitable rail fastening system 14 on rail ties 16 which are in turn supported within a rail bed 18 of aggregate, concrete, or other material. The rail ties 16 are made of a cast material such as concrete or a composite material, for example, and as discussed further below, each rail tie 14 includes a rail tie pad 20 in accordance with the present disclosure which is joined to the rail tie 16. Each rail tie 16 includes a top side 22 to which the rails 12 are joined via the fail fastening system 14, an opposite bottom side (unnumbered) to which the rail tie pad 20 is joined in the manner discussed below, and a plurality of substantially vertical side walls 26.

Referring to FIG. 2, a rail tie pad 20 is shown in accordance with a first embodiment, which generally includes a flexible, polymeric body made of a rubber of elastomeric material, for example. The material of rail tie pad may have a hardness of as little as 40, 50 or 60 Shore A, or as great as 70, 80, or 90 Shore A, or a hardness within any range defined between any two of the foregoing values, such as from 40 to 90 Shore A, from 50 to 80 Shore A, or from 60 to 70 Shore A, for example.

The rail tie pad 20 includes, with further reference to FIGS. 3 and 4, an upper surface 30 and a lower surface 32, as well as a first and second sides 34 and 36 and, referring back to FIG. 2, first and second ends 38 and 40. The rail tie pad 20 may be made according to an extrusion-based method in which an elongate extrusion having the profile shown in cross-section in FIGS. 2 and 3 is cut to a desired length to form ends 38 and 40 of rail tie pad 20.

Referring to FIGS. 3 and 4, upper surface 30 and lower surface 32 each include a plurality of undulations with alternating concave portions 42 and convex portions 44. As shown, the concave portions 42 of the undulations of the upper surface 30 are vertically aligned with convex portions 44 of the undulations of the lower surface, and the convex portions 44 of undulations of the upper surface 30 are vertically aligned with the concave portions 42 of undulations of the lower surface 32.

Referring to FIG. 4, a vertical thickness T₁ is defined as the vertical distance between a convex portion 44 in an undulation of the upper surface 30 and a convex portion 44 of an undulation of the lower surface 32. A vertical thickness T₂ is defined as the vertical distance between either a convex portion 44 in an undulation of the upper surface 30 and a horizontally aligned concave portion 42 of an undulation of the lower surface 32, or the vertical distance between a concave portion 42 in an undulation of the upper surface 30 and a horizontally aligned convex portion 44 of an undulation of the lower surface 32. For the purposes of this disclosure, the term “vertical thickness” as used between the upper surface 30 and the lower surface 32 of the rail tie pad 20 encompasses either or both of vertical thickness T₁ and T₂.

Referring to FIGS. 2-4, rail tie pad 20 includes a pair of side anchor portions 50 respectfully disposed at the first and second opposite sides 34 and 36 of the pad 20 and which, as best shown in the perspective view of FIG. 2, extend in length substantially entirely along the first and second sides 34 and 36. More specifically, with reference to FIG. 4, the side anchor portions 50 each extend upwardly from upper surface 30 of pad 20 to define a vertical thickness greater than the vertical thickness of pad 20, and are positioned at the terminal or outermost ends of the respective first and second opposite sides 34 and 36 sides of the pad 20 for reasons discussed further below.

Side anchor portions 50 each have a substantially triangular shape or profile in cross-section, and include a vertical outermost wall 52 which, when rail tie pad 20 is cast within a cast rail tie 16 as shown in FIG. 4, are disposed substantially vertically flush with a respective side wall 26 of the cast rail tie 16. Referring to FIG. 4, each vertical wall 52 is joined to the lower surface 32 of rail tie pad 20 via a rounded corner 54 having a generally large radius in order to aid in deflecting objects, such as forklift tines, for example, that may contact the side anchor portions 50 of rail tie pad 20 during transport and/or positioning of the rail tie pad 20 during installation. In this manner, the rounded corners 54 aid in maintaining the integral, fixed connection between side anchor portions 50 of rail tie pad 20 and the cast rail tie 16.

Side anchor portions 50 also each include at least one anchor projection 56 projecting therefrom for embedment within the cast material of the cast rail tie 16. In the embodiment shown in FIGS. 2-4, anchor projection 56 is T-shaped, including a central stem portion 58 and an arrow-shaped head portion 60. As illustrated in FIG. 4, anchor projections 56 may be disposed at an angle A₁ with respect to upper surface 30 of rail tie pad 20, which may be as little as 20, 30, or 40 degrees, or as great as 50, 60, or 70 degrees, for example, or may be an angle within any range defined between any two of the forgoing values, such as 20 to 70 degrees, 30 to 60 degrees, or 40 to 50 degrees, for example. In one embodiment, angle A₁ is 45 degrees.

Advantageously, in the event that a side anchor portion 50 is contacted by an external object in a direction generally perpendicular to its vertical wall 52, anchor portion 50 will tend to be subjected to a dislodgement force which generally in a direction aligned along a 45 degree angle with respect to the vertical wall 52, and the positioning of anchor projection 56 at angle A₁ positions anchor portion directly in line with, yet opposed to, the dislodgement force to fully resist the dislodgement force.

Referring to FIGS. 3 and 4, rail tie pad 20 may further include at least one central anchor portion 62 positioned between side anchor portions 50, for example, as shown in FIG. 3, rail tie pad 20 includes a single central anchor portion 62 positioned equidistantly between side anchor portions at the lateral center of rail tie pad 20, with central anchor portion 62 also including an increased thickness with respect to the vertical thickness of rail tie pad 20. Similar to side anchor portions 50, central anchor portion 62 also includes a T-shaped anchor projection 64 for embedment within the material of cast rail tie 16, and also extends upwardly from upper surface 30 of pad 20 to define a vertical thickness greater than the vertical thickness of pad 20.

When rail tie 16 is cast, a cast material, such as concrete, is poured a suitable mold (not shown) or other form structure to form the body of the tie 16. Then, when the cast material is still wet and uncured, raid tie pad 20 is placed upside-down on top of the case tie body with upper surface 30 of pad 20 engaging the cast material, and side anchor portions 50 and central anchor portion 62 pressed into the cast material. A vibration device (not shown) is typically used to vibrate the entire form structure, or a portion of the form structure such as a plate positioned over the rail tie pad 20 across the top of the form structure. The application of vibrations to the cast tie body and rail tie pad 20 firmly engages and presses the upper surface 30 of the rail tie pad 20 into the cast material, and also fully presses and embeds the side anchor portions 50 and central anchor portion 62 within the cast material. In this manner, the cast material completely surrounds and fills the spaces between side and central anchor portions 50 and 62, and completely fills concave portions 42 of the undulations of upper surface 30 of rail tie pad 20. Upon curing of the cast material, rail tie pad 20 will be firmly joined and fixed to the cast tie 16, with the embedment of side and central anchor portions 50 and 62 within the cast material of tie 16 providing a robust, integral connection between rail tie pad 20 and the bottom side 24 of cast rail tie 16 which is resistant to separation. Additionally, the filling of the cast material within concave portions 42 of the undulations of upper surface 30 of rail tie pad 20 assists with the lateral fixation of rail tie pad 20 to the bottom side 24 of cast rail tie 16.

In another process, rail tie pad 20 may be placed in the bottom of a mold or form structure and the cast material poured into the mold or form structure onto rail tie pad 20, followed by optionally applying vibrations to the cast structure to firmly engage and press the upper surface 30 of the rail tie pad 20 into the cast material, and also fully press and embed the side anchor portions 50 and central anchor portion 62 within the cast material, as described above.

The rail tie pads disclosed herein need not be formed monolithically of a single material, but rather may be formed of at least two materials in a dual-durometer configuration. For example, referring to FIG. 6, rail tie pad 20 according to FIGS. 2-4 is shown according to an alternate configuration in which a first portion 66, shown as a majority portion of pad 20, is formed of a first, relatively soft rubber or elastomeric material such as that described above. A second portion 68 of pad 20, shown in FIG. 6 as a minority portion of pad 20, is formed of a second rubber or elastomeric material, or a plastic material, which is relatively harder than the material of first portion 66. In the embodiment of FIG. 6, the anchor projections 56 and 64 of anchor portions 50 and 62, respectively, are formed in second portion 68 of the relatively harder material to provide more rigidity to anchor projections 56 and 64 to further prevent potential pull-out or separation of rail tie pad 20 from cast rail tie 16.

Referring to FIGS. 7-9, a rail tie pad 70 according to a second embodiment is shown which, except as described below, is identical to rail tie pad 20 of FIGS. 2-4 described above, and the same reference numerals have been used to designate identical components therebetween. Rail tie pad 70 includes side anchor portions 50 having anchor projections 72 formed as inverted undercut, or dovetail-shaped, projections, as well as three central anchor portions 62 with anchor projections 74 of the same shape as anchor projections 72, with central anchor portions 62 relatively evenly spaced with respect to one another along the horizontal extent of rail tie pad 70.

Referring to FIGS. 10-12, a rail tie pad 80 according to a third embodiment is shown which, except as described below, is identical to rail tie pads 20 and 70 of FIGS. 2-4 described above, and the same reference numerals have been used to designate identical components therebetween. Rail tie pad 80 includes side anchor portions 50 having anchor projections 82 having a T-shape though, as shown in FIG. 11, are disposed at an angle A₂ of approximately 60 degrees with respect to upper surface 30 of rail tie pad 80.

Referring to FIG. 13, a rail tie pad 90 according to a still further embodiment is shown which, except as described below, is identical to rail tie pad 20 of FIGS. 2-4 described above, and the same reference numerals have been used to designate identical components therebetween. Side anchor portions 92 of rail tie pad 90 are formed as elongate extensions, including vertical walls 94 which extend along the side walls 26 of cast rail tie 16 a distance as little as 1 inch, 2 inches, or 3 inches, or as great as 4 inches, 5 inches, or 6 inches, or within any range defied between any two of the foregoing values, such as 1 to 6 inches, 2 to 5 inches, or 3 to 4 inches, for example.

In this manner, side anchor portions 92 provide a greater overlap with side walls 26 of cast rail tie 16 to enhance the connection between rail tie pad 90 and cast rail tie 16 and further aid in deflecting objects, such as forklift tines, for example, that may contact the side anchor portions 92 of rail tie pad 20 along their vertical extent during transport and/or positioning of the rail tie pad 90 during installation.

As used herein, the phrase “within any range defined between any two of the foregoing values” literally means that any range may be selected from any two of the values listed prior to such phrase regardless of whether the values are in the lower part of the listing or in the higher part of the listing. For example, a pair of values may be selected from two lower values, two higher values, or a lower value and a higher value.

It should be understood that the foregoing description is only illustrative of the present disclosure. Various alternatives and modifications can be devised by those skilled in the art without departing from the disclosure. Accordingly, the present disclosure is intended to embrace all such alternatives, modifications and variances that fall within the scope of the appended claims.

Claims

1. A rail tie pad for use with a cast rail tie, comprising: a flexible, polymeric body having first and second opposite sides and including, when viewed in cross-section: an upper surface and a lower surface defining a first vertical thickness therebetween, and each including a plurality of undulations with alternating concave portions and convex portions; anda pair of side anchor portions respectively disposed at the first and second opposite sides of the pad, the side anchor portions each having a second vertical thickness greater than the first vertical thickness, each side anchor portion extending upwardly from the upper surface and including at least one anchor projection for embedment within a cast rail tie.

2. The rail tie pad of claim 1, wherein the concave portions of the undulations of the upper surface are vertically aligned with the convex portions of the undulations of the lower surface, and the convex portions of the undulations of the upper surface are vertically aligned with the concave portions of the undulations of the lower surface.

3. The rail tie pad of claim 1, wherein the side anchor portions each extend substantially entirely along the first and second opposite sides of the pad.

4. The rail tie pad of claim 1, further comprising at least one central anchor portion disposed between the pair of side anchor portions, each central anchor portion having a third vertical thickness greater than the first vertical thickness and extending upwardly from the upper surface, each central anchor portion further including at least one anchor projection for embedment within a cast rail tie.

5. The rail tie pad of claim 1, wherein the side anchor portions each have a substantially triangular profile when viewed in cross-section.

6. The rail tie pad of claim 1, wherein the side anchor portions include vertical outermost walls which, when the rail tie pad is cast within a cast rail tie, are disposed substantially vertically flush with side walls of the cast rail tie.

7. The rail tie pad of claim 6, wherein, when viewed in cross-section, the vertical outermost walls of the side anchor portions are each joined to the lower surface of the rail tie pad via a rounded corner.

8. The rail tie pad of claim 7, wherein the anchor projections of the side anchor portions each extend at an angle with respect to the top surface of the rail tie pad.

9. The rail tie pad of claim 1, wherein the polymeric body is made of an elastomer having a hardness between 50 Shore A and 80 Shore A.

10. A cast rail tie, comprising: a cast tie body including a top side, a bottom side, and a plurality of side walls; anda rail tie pad joined to the bottom side of the cast body, the rail tie pad including a flexible, polymeric body having first and second opposite sides and, when viewed in cross-section, an upper surface and a lower surface defining a first vertical thickness therebetween, the rail tie pad further including a pair of side anchor portions respectively disposed at the first and second opposite sides of the pad, each side anchor portion including at least one anchor projection adapted for embedment within a cast rail tie.

11. The cast rail tie of claim 10, wherein the side anchor portions extend substantially entirely along the first and second opposite sides of the rail tie pad.

12. The cast rail tie of claim 10, wherein the side anchor portions of the rail tie pad each extend upwardly from the upper surface and have a second vertical thickness greater than the first vertical thickness.

13. The cast rail tie of claim 10, wherein the side anchor portions of the rail tie pad include vertical outermost walls which are disposed substantially vertically flush with respective side walls of the cast tie body.

14. The cast rail tie of claim 10, wherein the side anchor portions of the rail tie pad, when viewed in cross section, extend vertically upwardly beyond the bottom side of the cast tie body.

15. The cast rail tie of claim 10, wherein, when viewed in cross-section, the vertical outermost walls of the side anchor portions of the rail tie pad are each joined to the lower surface of the rail tie pad via a rounded corner.

16. The cast rail tie of claim 10, wherein the anchor projections of the side anchor portions extend at an angle with respect to the top surface of the rail tie pad.

17. The cast rail tie of claim 10, wherein the upper surface and the lower surface of the rail tie pad each include a plurality of undulations with alternating concave portions and convex portions.

18. The cast rail tie of claim 17, wherein the concave portions of the undulations of the upper surface are vertically aligned with the convex portions of the undulations of the lower surface of the rail tie pad, and the convex portions of the undulations of the upper surface are vertically aligned with the concave portions of the undulations of the lower surface of the rail tie pad.

19. The cast rail tie of claim 10, further comprising at least one central anchor portion disposed between the pair of side anchor portions, each central anchor portion having a third vertical thickness greater than the first vertical thickness and extending upwardly from the upper surface, each central anchor portion further including at least one anchor projection embedded within the cast tie body.

20. The cast rail tie of claim 10, wherein a material of the cast tie body entirely fills each of the concave portions of the undulations of the upper surface of the rail tie pad.